Mercurial > demo / ffi/quiche.h

 // Copyright (C) 2018-2019, Cloudflare, Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //
 //     * Redistributions in binary form must reproduce the above copyright
 //       notice, this list of conditions and the following disclaimer in the
 //       documentation and/or other materials provided with the distribution.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 // IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 // THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef QUICHE_H
 #define QUICHE_H
 
 #if defined(__cplusplus)
 extern "C" {
 #endif
 
 #include <stdint.h>
 #include <stdbool.h>
 #include <stddef.h>
 
 #if defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__)
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #include <time.h>
 #else
 #include <sys/socket.h>
 #include <sys/time.h>
 #endif
 
 #ifdef __unix__
 #include <sys/types.h>
 #endif
 #ifdef _MSC_VER
 #include <BaseTsd.h>
 #define ssize_t SSIZE_T
 #endif
 
 // QUIC transport API.
 //
 
 // The current QUIC wire version.
 #define QUICHE_PROTOCOL_VERSION 0x00000001
 
 // The maximum length of a connection ID.
 #define QUICHE_MAX_CONN_ID_LEN 20
 
 // The minimum length of Initial packets sent by a client.
 #define QUICHE_MIN_CLIENT_INITIAL_LEN 1200
 
 enum quiche_error {
     // There is no more work to do.
     QUICHE_ERR_DONE = -1,
 
     // The provided buffer is too short.
     QUICHE_ERR_BUFFER_TOO_SHORT = -2,
 
     // The provided packet cannot be parsed because its version is unknown.
     QUICHE_ERR_UNKNOWN_VERSION = -3,
 
     // The provided packet cannot be parsed because it contains an invalid
     // frame.
     QUICHE_ERR_INVALID_FRAME = -4,
 
     // The provided packet cannot be parsed.
     QUICHE_ERR_INVALID_PACKET = -5,
 
     // The operation cannot be completed because the connection is in an
     // invalid state.
     QUICHE_ERR_INVALID_STATE = -6,
 
     // The operation cannot be completed because the stream is in an
     // invalid state.
     QUICHE_ERR_INVALID_STREAM_STATE = -7,
 
     // The peer's transport params cannot be parsed.
     QUICHE_ERR_INVALID_TRANSPORT_PARAM = -8,
 
     // A cryptographic operation failed.
     QUICHE_ERR_CRYPTO_FAIL = -9,
 
     // The TLS handshake failed.
     QUICHE_ERR_TLS_FAIL = -10,
 
     // The peer violated the local flow control limits.
     QUICHE_ERR_FLOW_CONTROL = -11,
 
     // The peer violated the local stream limits.
     QUICHE_ERR_STREAM_LIMIT = -12,
 
     // The specified stream was stopped by the peer.
     QUICHE_ERR_STREAM_STOPPED = -15,
 
     // The specified stream was reset by the peer.
     QUICHE_ERR_STREAM_RESET = -16,
 
     // The received data exceeds the stream's final size.
     QUICHE_ERR_FINAL_SIZE = -13,
 
     // Error in congestion control.
     QUICHE_ERR_CONGESTION_CONTROL = -14,
 
     // Too many identifiers were provided.
     QUICHE_ERR_ID_LIMIT = -17,
 
     // Not enough available identifiers.
     QUICHE_ERR_OUT_OF_IDENTIFIERS = -18,
 
     // Error in key update.
     QUICHE_ERR_KEY_UPDATE = -19,
 };
 
 // Returns a human readable string with the quiche version number.
 const char *quiche_version(void);
 
 // Enables logging. |cb| will be called with log messages
 int quiche_enable_debug_logging(void (*cb)(const char *line, void *argp),
                                 void *argp);
 
 // Stores configuration shared between multiple connections.
 typedef struct quiche_config quiche_config;
 
 // Creates a config object with the given version.
 quiche_config *quiche_config_new(uint32_t version);
 
 // Configures the given certificate chain.
 int quiche_config_load_cert_chain_from_pem_file(quiche_config *config,
                                                 const char *path);
 
 // Configures the given private key.
 int quiche_config_load_priv_key_from_pem_file(quiche_config *config,
                                               const char *path);
 
 // Specifies a file where trusted CA certificates are stored for the purposes of certificate verification.
 int quiche_config_load_verify_locations_from_file(quiche_config *config,
                                                   const char *path);
 
 // Specifies a directory where trusted CA certificates are stored for the purposes of certificate verification.
 int quiche_config_load_verify_locations_from_directory(quiche_config *config,
                                                        const char *path);
 
 // Configures whether to verify the peer's certificate.
 void quiche_config_verify_peer(quiche_config *config, bool v);
 
 // Configures whether to send GREASE.
 void quiche_config_grease(quiche_config *config, bool v);
 
 // Enables logging of secrets.
 void quiche_config_log_keys(quiche_config *config);
 
 // Enables sending or receiving early data.
 void quiche_config_enable_early_data(quiche_config *config);
 
 // Configures the list of supported application protocols.
 int quiche_config_set_application_protos(quiche_config *config,
                                          const uint8_t *protos,
                                          size_t protos_len);
 
 // Sets the `max_idle_timeout` transport parameter, in milliseconds, default is
 // no timeout.
 void quiche_config_set_max_idle_timeout(quiche_config *config, uint64_t v);
 
 // Sets the `max_udp_payload_size transport` parameter.
 void quiche_config_set_max_recv_udp_payload_size(quiche_config *config, size_t v);
 
 // Sets the maximum outgoing UDP payload size.
 void quiche_config_set_max_send_udp_payload_size(quiche_config *config, size_t v);
 
 // Sets the `initial_max_data` transport parameter.
 void quiche_config_set_initial_max_data(quiche_config *config, uint64_t v);
 
 // Sets the `initial_max_stream_data_bidi_local` transport parameter.
 void quiche_config_set_initial_max_stream_data_bidi_local(quiche_config *config, uint64_t v);
 
 // Sets the `initial_max_stream_data_bidi_remote` transport parameter.
 void quiche_config_set_initial_max_stream_data_bidi_remote(quiche_config *config, uint64_t v);
 
 // Sets the `initial_max_stream_data_uni` transport parameter.
 void quiche_config_set_initial_max_stream_data_uni(quiche_config *config, uint64_t v);
 
 // Sets the `initial_max_streams_bidi` transport parameter.
 void quiche_config_set_initial_max_streams_bidi(quiche_config *config, uint64_t v);
 
 // Sets the `initial_max_streams_uni` transport parameter.
 void quiche_config_set_initial_max_streams_uni(quiche_config *config, uint64_t v);
 
 // Sets the `ack_delay_exponent` transport parameter.
 void quiche_config_set_ack_delay_exponent(quiche_config *config, uint64_t v);
 
 // Sets the `max_ack_delay` transport parameter.
 void quiche_config_set_max_ack_delay(quiche_config *config, uint64_t v);
 
 // Sets the `disable_active_migration` transport parameter.
 void quiche_config_set_disable_active_migration(quiche_config *config, bool v);
 
 enum quiche_cc_algorithm {
     QUICHE_CC_RENO = 0,
     QUICHE_CC_CUBIC = 1,
     QUICHE_CC_BBR = 2,
 };
 
 // Sets the congestion control algorithm used.
 void quiche_config_set_cc_algorithm(quiche_config *config, enum quiche_cc_algorithm algo);
 
 // Configures whether to use HyStart++.
 void quiche_config_enable_hystart(quiche_config *config, bool v);
 
 // Configures whether to enable pacing (enabled by default).
 void quiche_config_enable_pacing(quiche_config *config, bool v);
 
 // Configures max pacing rate to be used.
 void quiche_config_set_max_pacing_rate(quiche_config *config, uint64_t v);
 
 // Configures whether to enable receiving DATAGRAM frames.
 void quiche_config_enable_dgram(quiche_config *config, bool enabled,
                                 size_t recv_queue_len,
                                 size_t send_queue_len);
 
 // Sets the maximum connection window.
 void quiche_config_set_max_connection_window(quiche_config *config, uint64_t v);
 
 // Sets the maximum stream window.
 void quiche_config_set_max_stream_window(quiche_config *config, uint64_t v);
 
 // Sets the limit of active connection IDs.
 void quiche_config_set_active_connection_id_limit(quiche_config *config, uint64_t v);
 
 // Sets the initial stateless reset token. |v| must contain 16 bytes, otherwise the behaviour is undefined.
 void quiche_config_set_stateless_reset_token(quiche_config *config, const uint8_t *v);
 
 // Frees the config object.
 void quiche_config_free(quiche_config *config);
 
 // Extracts version, type, source / destination connection ID and address
 // verification token from the packet in |buf|.
 int quiche_header_info(const uint8_t *buf, size_t buf_len, size_t dcil,
                        uint32_t *version, uint8_t *type,
                        uint8_t *scid, size_t *scid_len,
                        uint8_t *dcid, size_t *dcid_len,
                        uint8_t *token, size_t *token_len);
 
 // A QUIC connection.
 typedef struct quiche_conn quiche_conn;
 
 // Creates a new server-side connection.
 quiche_conn *quiche_accept(const uint8_t *scid, size_t scid_len,
                            const uint8_t *odcid, size_t odcid_len,
                            const struct sockaddr *local, size_t local_len,
                            const struct sockaddr *peer, size_t peer_len,
                            quiche_config *config);
 
 // Creates a new client-side connection.
 quiche_conn *quiche_connect(const char *server_name,
                             const uint8_t *scid, size_t scid_len,
                             const struct sockaddr *local, size_t local_len,
                             const struct sockaddr *peer, size_t peer_len,
                             quiche_config *config);
 
 // Writes a version negotiation packet.
 ssize_t quiche_negotiate_version(const uint8_t *scid, size_t scid_len,
                                  const uint8_t *dcid, size_t dcid_len,
                                  uint8_t *out, size_t out_len);
 
 // Writes a retry packet.
 ssize_t quiche_retry(const uint8_t *scid, size_t scid_len,
                      const uint8_t *dcid, size_t dcid_len,
                      const uint8_t *new_scid, size_t new_scid_len,
                      const uint8_t *token, size_t token_len,
                      uint32_t version, uint8_t *out, size_t out_len);
 
 // Returns true if the given protocol version is supported.
 bool quiche_version_is_supported(uint32_t version);
 
 quiche_conn *quiche_conn_new_with_tls(const uint8_t *scid, size_t scid_len,
                                       const uint8_t *odcid, size_t odcid_len,
                                       const struct sockaddr *local, size_t local_len,
                                       const struct sockaddr *peer, size_t peer_len,
                                       quiche_config *config, void *ssl,
                                       bool is_server);
 
 // Enables keylog to the specified file path. Returns true on success.
 bool quiche_conn_set_keylog_path(quiche_conn *conn, const char *path);
 
 // Enables keylog to the specified file descriptor. Unix only.
 void quiche_conn_set_keylog_fd(quiche_conn *conn, int fd);
 
 // Enables qlog to the specified file path. Returns true on success.
 bool quiche_conn_set_qlog_path(quiche_conn *conn, const char *path,
                           const char *log_title, const char *log_desc);
 
 // Enables qlog to the specified file descriptor. Unix only.
 void quiche_conn_set_qlog_fd(quiche_conn *conn, int fd, const char *log_title,
                              const char *log_desc);
 
 // Configures the given session for resumption.
 int quiche_conn_set_session(quiche_conn *conn, const uint8_t *buf, size_t buf_len);
 
 typedef struct {
     // The remote address the packet was received from.
     struct sockaddr *from;
     socklen_t from_len;
 
     // The local address the packet was received on.
     struct sockaddr *to;
     socklen_t to_len;
 } quiche_recv_info;
 
 // Processes QUIC packets received from the peer.
 ssize_t quiche_conn_recv(quiche_conn *conn, uint8_t *buf, size_t buf_len,
                          const quiche_recv_info *info);
 
 typedef struct {
     // The local address the packet should be sent from.
     struct sockaddr_storage from;
     socklen_t from_len;
 
     // The remote address the packet should be sent to.
     struct sockaddr_storage to;
     socklen_t to_len;
 
     // The time to send the packet out.
     struct timespec at;
 } quiche_send_info;
 
 // Writes a single QUIC packet to be sent to the peer.
 ssize_t quiche_conn_send(quiche_conn *conn, uint8_t *out, size_t out_len,
                          quiche_send_info *out_info);
 
 // Returns the size of the send quantum, in bytes.
 size_t quiche_conn_send_quantum(const quiche_conn *conn);
 
 // Reads contiguous data from a stream.
 ssize_t quiche_conn_stream_recv(quiche_conn *conn, uint64_t stream_id,
                                 uint8_t *out, size_t buf_len, bool *fin);
 
 // Writes data to a stream.
 ssize_t quiche_conn_stream_send(quiche_conn *conn, uint64_t stream_id,
                                 const uint8_t *buf, size_t buf_len, bool fin);
 
 // The side of the stream to be shut down.
 enum quiche_shutdown {
     QUICHE_SHUTDOWN_READ = 0,
     QUICHE_SHUTDOWN_WRITE = 1,
 };
 
 // Sets the priority for a stream.
 int quiche_conn_stream_priority(quiche_conn *conn, uint64_t stream_id,
                                 uint8_t urgency, bool incremental);
 
 // Shuts down reading or writing from/to the specified stream.
 int quiche_conn_stream_shutdown(quiche_conn *conn, uint64_t stream_id,
                                 enum quiche_shutdown direction, uint64_t err);
 
 // Returns the stream's send capacity in bytes.
 ssize_t quiche_conn_stream_capacity(const quiche_conn *conn, uint64_t stream_id);
 
 // Returns true if the stream has data that can be read.
 bool quiche_conn_stream_readable(const quiche_conn *conn, uint64_t stream_id);
 
 // Returns the next stream that has data to read, or -1 if no such stream is
 // available.
 int64_t quiche_conn_stream_readable_next(quiche_conn *conn);
 
 // Returns true if the stream has enough send capacity.
 //
 // On error a value lower than 0 is returned.
 int quiche_conn_stream_writable(quiche_conn *conn, uint64_t stream_id, size_t len);
 
 // Returns the next stream that can be written to, or -1 if no such stream is
 // available.
 int64_t quiche_conn_stream_writable_next(quiche_conn *conn);
 
 // Returns true if all the data has been read from the specified stream.
 bool quiche_conn_stream_finished(const quiche_conn *conn, uint64_t stream_id);
 
 typedef struct quiche_stream_iter quiche_stream_iter;
 
 // Returns an iterator over streams that have outstanding data to read.
 quiche_stream_iter *quiche_conn_readable(const quiche_conn *conn);
 
 // Returns an iterator over streams that can be written to.
 quiche_stream_iter *quiche_conn_writable(const quiche_conn *conn);
 
 // Returns the maximum possible size of egress UDP payloads.
 size_t quiche_conn_max_send_udp_payload_size(const quiche_conn *conn);
 
 // Returns the amount of time until the next timeout event, in nanoseconds.
 uint64_t quiche_conn_timeout_as_nanos(const quiche_conn *conn);
 
 // Returns the amount of time until the next timeout event, in milliseconds.
 uint64_t quiche_conn_timeout_as_millis(const quiche_conn *conn);
 
 // Processes a timeout event.
 void quiche_conn_on_timeout(quiche_conn *conn);
 
 // Closes the connection with the given error and reason.
 int quiche_conn_close(quiche_conn *conn, bool app, uint64_t err,
                       const uint8_t *reason, size_t reason_len);
 
 // Returns a string uniquely representing the connection.
 void quiche_conn_trace_id(const quiche_conn *conn, const uint8_t **out, size_t *out_len);
 
 // Returns the source connection ID.
 void quiche_conn_source_id(const quiche_conn *conn, const uint8_t **out, size_t *out_len);
 
 // Returns the destination connection ID.
 void quiche_conn_destination_id(const quiche_conn *conn, const uint8_t **out, size_t *out_len);
 
 // Returns the negotiated ALPN protocol.
 void quiche_conn_application_proto(const quiche_conn *conn, const uint8_t **out,
                                    size_t *out_len);
 
 // Returns the peer's leaf certificate (if any) as a DER-encoded buffer.
 void quiche_conn_peer_cert(const quiche_conn *conn, const uint8_t **out, size_t *out_len);
 
 // Returns the serialized cryptographic session for the connection.
 void quiche_conn_session(const quiche_conn *conn, const uint8_t **out, size_t *out_len);
 
 // Returns true if the connection handshake is complete.
 bool quiche_conn_is_established(const quiche_conn *conn);
 
 // Returns true if the connection has a pending handshake that has progressed
 // enough to send or receive early data.
 bool quiche_conn_is_in_early_data(const quiche_conn *conn);
 
 // Returns whether there is stream or DATAGRAM data available to read.
 bool quiche_conn_is_readable(const quiche_conn *conn);
 
 // Returns true if the connection is draining.
 bool quiche_conn_is_draining(const quiche_conn *conn);
 
 // Returns the number of bidirectional streams that can be created
 // before the peer's stream count limit is reached.
 uint64_t quiche_conn_peer_streams_left_bidi(const quiche_conn *conn);
 
 // Returns the number of unidirectional streams that can be created
 // before the peer's stream count limit is reached.
 uint64_t quiche_conn_peer_streams_left_uni(const quiche_conn *conn);
 
 // Returns true if the connection is closed.
 bool quiche_conn_is_closed(const quiche_conn *conn);
 
 // Returns true if the connection was closed due to the idle timeout.
 bool quiche_conn_is_timed_out(const quiche_conn *conn);
 
 // Returns true if a connection error was received, and updates the provided
 // parameters accordingly.
 bool quiche_conn_peer_error(const quiche_conn *conn,
                             bool *is_app,
                             uint64_t *error_code,
                             const uint8_t **reason,
                             size_t *reason_len);
 
 // Returns true if a connection error was queued or sent, and updates the provided
 // parameters accordingly.
 bool quiche_conn_local_error(const quiche_conn *conn,
                              bool *is_app,
                              uint64_t *error_code,
                              const uint8_t **reason,
                              size_t *reason_len);
 
 // Initializes the stream's application data.
 //
 // Stream data can only be initialized once. Additional calls to this method
 // will fail.
 //
 // Note that the application is responsible for freeing the data.
 int quiche_conn_stream_init_application_data(quiche_conn *conn,
                                              uint64_t stream_id,
                                              void *data);
 
 // Returns the stream's application data, if any was initialized.
 void *quiche_conn_stream_application_data(quiche_conn *conn, uint64_t stream_id);
 
 // Fetches the next stream from the given iterator. Returns false if there are
 // no more elements in the iterator.
 bool quiche_stream_iter_next(quiche_stream_iter *iter, uint64_t *stream_id);
 
 // Frees the given stream iterator object.
 void quiche_stream_iter_free(quiche_stream_iter *iter);
 
 typedef struct {
     // The number of QUIC packets received on this connection.
     size_t recv;
 
     // The number of QUIC packets sent on this connection.
     size_t sent;
 
     // The number of QUIC packets that were lost.
     size_t lost;
 
     // The number of sent QUIC packets with retransmitted data.
     size_t retrans;
 
     // The number of sent bytes.
     uint64_t sent_bytes;
 
     // The number of received bytes.
     uint64_t recv_bytes;
 
     // The number of bytes lost.
     uint64_t lost_bytes;
 
     // The number of stream bytes retransmitted.
     uint64_t stream_retrans_bytes;
 
     // The number of known paths for the connection.
     size_t paths_count;
 
     // The maximum idle timeout.
     uint64_t peer_max_idle_timeout;
 
     // The maximum UDP payload size.
     uint64_t peer_max_udp_payload_size;
 
     // The initial flow control maximum data for the connection.
     uint64_t peer_initial_max_data;
 
     // The initial flow control maximum data for local bidirectional streams.
     uint64_t peer_initial_max_stream_data_bidi_local;
 
     // The initial flow control maximum data for remote bidirectional streams.
     uint64_t peer_initial_max_stream_data_bidi_remote;
 
     // The initial flow control maximum data for unidirectional streams.
     uint64_t peer_initial_max_stream_data_uni;
 
     // The initial maximum bidirectional streams.
     uint64_t peer_initial_max_streams_bidi;
 
     // The initial maximum unidirectional streams.
     uint64_t peer_initial_max_streams_uni;
 
     // The ACK delay exponent.
     uint64_t peer_ack_delay_exponent;
 
     // The max ACK delay.
     uint64_t peer_max_ack_delay;
 
     // Whether active migration is disabled.
     bool peer_disable_active_migration;
 
     // The active connection ID limit.
     uint64_t peer_active_conn_id_limit;
 
     // DATAGRAM frame extension parameter, if any.
     ssize_t peer_max_datagram_frame_size;
 } quiche_stats;
 
 // Collects and returns statistics about the connection.
 void quiche_conn_stats(const quiche_conn *conn, quiche_stats *out);
 
 typedef struct {
     // The local address used by this path.
     struct sockaddr_storage local_addr;
     socklen_t local_addr_len;
 
     // The peer address seen by this path.
     struct sockaddr_storage peer_addr;
     socklen_t peer_addr_len;
 
     // The validation state of the path.
     ssize_t validation_state;
 
     // Whether this path is active.
     bool active;
 
     // The number of QUIC packets received on this path.
     size_t recv;
 
     // The number of QUIC packets sent on this path.
     size_t sent;
 
     // The number of QUIC packets that were lost on this path.
     size_t lost;
 
     // The number of sent QUIC packets with retransmitted data on this path.
     size_t retrans;
 
     // The estimated round-trip time of the path (in nanoseconds).
     uint64_t rtt;
 
     // The size of the path's congestion window in bytes.
     size_t cwnd;
 
     // The number of sent bytes on this path.
     uint64_t sent_bytes;
 
     // The number of received bytes on this path.
     uint64_t recv_bytes;
 
     // The number of bytes lost on this path.
     uint64_t lost_bytes;
 
     // The number of stream bytes retransmitted on this path.
     uint64_t stream_retrans_bytes;
 
     // The current PMTU for the path.
     size_t pmtu;
 
     // The most recent data delivery rate estimate in bytes/s.
     uint64_t delivery_rate;
 } quiche_path_stats;
 
 
 // Collects and returns statistics about the specified path for the connection.
 //
 // The `idx` argument represent the path's index (also see the `paths_count`
 // field of `quiche_stats`).
 int quiche_conn_path_stats(const quiche_conn *conn, size_t idx, quiche_path_stats *out);
 
 // Returns whether or not this is a server-side connection.
 bool quiche_conn_is_server(const quiche_conn *conn);
 
 // Returns the maximum DATAGRAM payload that can be sent.
 ssize_t quiche_conn_dgram_max_writable_len(const quiche_conn *conn);
 
 // Returns the length of the first stored DATAGRAM.
 ssize_t quiche_conn_dgram_recv_front_len(const quiche_conn *conn);
 
 // Returns the number of items in the DATAGRAM receive queue.
 ssize_t quiche_conn_dgram_recv_queue_len(const quiche_conn *conn);
 
 // Returns the total size of all items in the DATAGRAM receive queue.
 ssize_t quiche_conn_dgram_recv_queue_byte_size(const quiche_conn *conn);
 
 // Returns the number of items in the DATAGRAM send queue.
 ssize_t quiche_conn_dgram_send_queue_len(const quiche_conn *conn);
 
 // Returns the total size of all items in the DATAGRAM send queue.
 ssize_t quiche_conn_dgram_send_queue_byte_size(const quiche_conn *conn);
 
 // Reads the first received DATAGRAM.
 ssize_t quiche_conn_dgram_recv(quiche_conn *conn, uint8_t *buf,
                                size_t buf_len);
 
 // Sends data in a DATAGRAM frame.
 ssize_t quiche_conn_dgram_send(quiche_conn *conn, const uint8_t *buf,
                                size_t buf_len);
 
 // Purges queued outgoing DATAGRAMs matching the predicate.
 void quiche_conn_dgram_purge_outgoing(quiche_conn *conn,
                                       bool (*f)(uint8_t *, size_t));
 
 // Schedule an ack-eliciting packet on the active path.
 ssize_t quiche_conn_send_ack_eliciting(quiche_conn *conn);
 
 // Schedule an ack-eliciting packet on the specified path.
 ssize_t quiche_conn_send_ack_eliciting_on_path(quiche_conn *conn,
                            const struct sockaddr *local, size_t local_len,
                            const struct sockaddr *peer, size_t peer_len);
 
 // Frees the connection object.
 void quiche_conn_free(quiche_conn *conn);
 
 
 // HTTP/3 API
 //
 
 // List of ALPN tokens of supported HTTP/3 versions.
 #define QUICHE_H3_APPLICATION_PROTOCOL "\x02h3\x05h3-29\x05h3-28\x05h3-27"
 
 enum quiche_h3_error {
     // There is no error or no work to do
     QUICHE_H3_ERR_DONE = -1,
 
     // The provided buffer is too short.
     QUICHE_H3_ERR_BUFFER_TOO_SHORT = -2,
 
     // Internal error in the HTTP/3 stack.
     QUICHE_H3_ERR_INTERNAL_ERROR = -3,
 
     // Endpoint detected that the peer is exhibiting behavior that causes.
     // excessive load.
     QUICHE_H3_ERR_EXCESSIVE_LOAD = -4,
 
     // Stream ID or Push ID greater that current maximum was
     // used incorrectly, such as exceeding a limit, reducing a limit,
     // or being reused.
     QUICHE_H3_ERR_ID_ERROR= -5,
 
     // The endpoint detected that its peer created a stream that it will not
     // accept.
     QUICHE_H3_ERR_STREAM_CREATION_ERROR = -6,
 
     // A required critical stream was closed.
     QUICHE_H3_ERR_CLOSED_CRITICAL_STREAM = -7,
 
     // No SETTINGS frame at beginning of control stream.
     QUICHE_H3_ERR_MISSING_SETTINGS = -8,
 
     // A frame was received which is not permitted in the current state.
     QUICHE_H3_ERR_FRAME_UNEXPECTED = -9,
 
     // Frame violated layout or size rules.
     QUICHE_H3_ERR_FRAME_ERROR = -10,
 
     // QPACK Header block decompression failure.
     QUICHE_H3_ERR_QPACK_DECOMPRESSION_FAILED = -11,
 
     // -12 was previously used for TransportError, skip it
 
     // The underlying QUIC stream (or connection) doesn't have enough capacity
     // for the operation to complete. The application should retry later on.
     QUICHE_H3_ERR_STREAM_BLOCKED = -13,
 
     // Error in the payload of a SETTINGS frame.
     QUICHE_H3_ERR_SETTINGS_ERROR = -14,
 
     // Server rejected request.
     QUICHE_H3_ERR_REQUEST_REJECTED = -15,
 
     // Request or its response cancelled.
     QUICHE_H3_ERR_REQUEST_CANCELLED = -16,
 
     // Client's request stream terminated without containing a full-formed
     // request.
     QUICHE_H3_ERR_REQUEST_INCOMPLETE = -17,
 
     // An HTTP message was malformed and cannot be processed.
     QUICHE_H3_ERR_MESSAGE_ERROR = -18,
 
     // The TCP connection established in response to a CONNECT request was
     // reset or abnormally closed.
     QUICHE_H3_ERR_CONNECT_ERROR = -19,
 
     // The requested operation cannot be served over HTTP/3. Peer should retry
     // over HTTP/1.1.
     QUICHE_H3_ERR_VERSION_FALLBACK = -20,
 
     // The following QUICHE_H3_TRANSPORT_ERR_* errors are propagated
     // from the QUIC transport layer.
 
     // See QUICHE_ERR_DONE.
     QUICHE_H3_TRANSPORT_ERR_DONE = QUICHE_ERR_DONE - 1000,
 
     // See QUICHE_ERR_BUFFER_TOO_SHORT.
     QUICHE_H3_TRANSPORT_ERR_BUFFER_TOO_SHORT = QUICHE_ERR_BUFFER_TOO_SHORT - 1000,
 
     // See QUICHE_ERR_UNKNOWN_VERSION.
     QUICHE_H3_TRANSPORT_ERR_UNKNOWN_VERSION = QUICHE_ERR_UNKNOWN_VERSION - 1000,
 
     // See QUICHE_ERR_INVALID_FRAME.
     QUICHE_H3_TRANSPORT_ERR_INVALID_FRAME = QUICHE_ERR_INVALID_FRAME - 1000,
 
     // See QUICHE_ERR_INVALID_PACKET.
     QUICHE_H3_TRANSPORT_ERR_INVALID_PACKET = QUICHE_ERR_INVALID_PACKET - 1000,
 
     // See QUICHE_ERR_INVALID_STATE.
     QUICHE_H3_TRANSPORT_ERR_INVALID_STATE = QUICHE_ERR_INVALID_STATE - 1000,
 
     // See QUICHE_ERR_INVALID_STREAM_STATE.
     QUICHE_H3_TRANSPORT_ERR_INVALID_STREAM_STATE = QUICHE_ERR_INVALID_STREAM_STATE - 1000,
 
     // See QUICHE_ERR_INVALID_TRANSPORT_PARAM.
     QUICHE_H3_TRANSPORT_ERR_INVALID_TRANSPORT_PARAM = QUICHE_ERR_INVALID_TRANSPORT_PARAM - 1000,
 
     // See QUICHE_ERR_CRYPTO_FAIL.
     QUICHE_H3_TRANSPORT_ERR_CRYPTO_FAIL = QUICHE_ERR_CRYPTO_FAIL - 1000,
 
     // See QUICHE_ERR_TLS_FAIL.
     QUICHE_H3_TRANSPORT_ERR_TLS_FAIL = QUICHE_ERR_TLS_FAIL - 1000,
 
     // See QUICHE_ERR_FLOW_CONTROL.
     QUICHE_H3_TRANSPORT_ERR_FLOW_CONTROL = QUICHE_ERR_FLOW_CONTROL - 1000,
 
     // See QUICHE_ERR_STREAM_LIMIT.
     QUICHE_H3_TRANSPORT_ERR_STREAM_LIMIT = QUICHE_ERR_STREAM_LIMIT - 1000,
 
     // See QUICHE_ERR_STREAM_STOPPED.
     QUICHE_H3_TRANSPORT_ERR_STREAM_STOPPED = QUICHE_ERR_STREAM_STOPPED - 1000,
 
     // See QUICHE_ERR_STREAM_RESET.
     QUICHE_H3_TRANSPORT_ERR_STREAM_RESET = QUICHE_ERR_STREAM_RESET - 1000,
 
     // See QUICHE_ERR_FINAL_SIZE.
     QUICHE_H3_TRANSPORT_ERR_FINAL_SIZE = QUICHE_ERR_FINAL_SIZE - 1000,
 
     // See QUICHE_ERR_CONGESTION_CONTROL.
     QUICHE_H3_TRANSPORT_ERR_CONGESTION_CONTROL = QUICHE_ERR_CONGESTION_CONTROL - 1000,
 
     // See QUICHE_ERR_ID_LIMIT.
     QUICHE_H3_TRANSPORT_ERR_ID_LIMIT = QUICHE_ERR_ID_LIMIT - 1000,
 
     // See QUICHE_ERR_OUT_OF_IDENTIFIERS.
     QUICHE_H3_TRANSPORT_ERR_OUT_OF_IDENTIFIERS = QUICHE_ERR_OUT_OF_IDENTIFIERS - 1000,
 
     // See QUICHE_ERR_KEY_UPDATE.
     QUICHE_H3_TRANSPORT_ERR_KEY_UPDATE = QUICHE_ERR_KEY_UPDATE - 1000,
 };
 
 // Stores configuration shared between multiple connections.
 typedef struct quiche_h3_config quiche_h3_config;
 
 // Creates an HTTP/3 config object with default settings values.
 quiche_h3_config *quiche_h3_config_new(void);
 
 // Sets the `SETTINGS_MAX_FIELD_SECTION_SIZE` setting.
 void quiche_h3_config_set_max_field_section_size(quiche_h3_config *config, uint64_t v);
 
 // Sets the `SETTINGS_QPACK_MAX_TABLE_CAPACITY` setting.
 void quiche_h3_config_set_qpack_max_table_capacity(quiche_h3_config *config, uint64_t v);
 
 // Sets the `SETTINGS_QPACK_BLOCKED_STREAMS` setting.
 void quiche_h3_config_set_qpack_blocked_streams(quiche_h3_config *config, uint64_t v);
 
 // Sets the `SETTINGS_ENABLE_CONNECT_PROTOCOL` setting.
 void quiche_h3_config_enable_extended_connect(quiche_h3_config *config, bool enabled);
 
 // Frees the HTTP/3 config object.
 void quiche_h3_config_free(quiche_h3_config *config);
 
 // An HTTP/3 connection.
 typedef struct quiche_h3_conn quiche_h3_conn;
 
 // Creates a new server-side connection.
 quiche_h3_conn *quiche_h3_accept(quiche_conn *quiche_conn,
                                  quiche_h3_config *config);
 
 // Creates a new HTTP/3 connection using the provided QUIC connection.
 quiche_h3_conn *quiche_h3_conn_new_with_transport(quiche_conn *quiche_conn,
                                                   quiche_h3_config *config);
 
 enum quiche_h3_event_type {
     QUICHE_H3_EVENT_HEADERS,
     QUICHE_H3_EVENT_DATA,
     QUICHE_H3_EVENT_FINISHED,
     QUICHE_H3_EVENT_DATAGRAM,
     QUICHE_H3_EVENT_GOAWAY,
     QUICHE_H3_EVENT_RESET,
     QUICHE_H3_EVENT_PRIORITY_UPDATE,
 };
 
 typedef struct quiche_h3_event quiche_h3_event;
 
 // Processes HTTP/3 data received from the peer.
 int64_t quiche_h3_conn_poll(quiche_h3_conn *conn, quiche_conn *quic_conn,
                             quiche_h3_event **ev);
 
 // Returns the type of the event.
 enum quiche_h3_event_type quiche_h3_event_type(quiche_h3_event *ev);
 
 // Iterates over the headers in the event.
 //
 // The `cb` callback will be called for each header in `ev`. `cb` should check
 // the validity of pseudo-headers and headers. If `cb` returns any value other
 // than `0`, processing will be interrupted and the value is returned to the
 // caller.
 int quiche_h3_event_for_each_header(quiche_h3_event *ev,
                                     int (*cb)(uint8_t *name, size_t name_len,
                                               uint8_t *value, size_t value_len,
                                               void *argp),
                                     void *argp);
 
 // Iterates over the peer's HTTP/3 settings.
 //
 // The `cb` callback will be called for each setting in `conn`.
 // If `cb` returns any value other than `0`, processing will be interrupted and
 // the value is returned to the caller.
 int quiche_h3_for_each_setting(quiche_h3_conn *conn,
                                int (*cb)(uint64_t identifier,
                                          uint64_t value, void *argp),
                                void *argp);
 
 // Check whether data will follow the headers on the stream.
 bool quiche_h3_event_headers_has_body(quiche_h3_event *ev);
 
 // Check whether or not extended connection is enabled by the peer
 bool quiche_h3_extended_connect_enabled_by_peer(quiche_h3_conn *conn);
 
 // Frees the HTTP/3 event object.
 void quiche_h3_event_free(quiche_h3_event *ev);
 
 typedef struct {
     const uint8_t *name;
     size_t name_len;
 
     const uint8_t *value;
     size_t value_len;
 } quiche_h3_header;
 
 // Extensible Priorities parameters.
 typedef struct {
     uint8_t urgency;
     bool incremental;
 } quiche_h3_priority;
 
 // Sends an HTTP/3 request.
 int64_t quiche_h3_send_request(quiche_h3_conn *conn, quiche_conn *quic_conn,
                                quiche_h3_header *headers, size_t headers_len,
                                bool fin);
 
 // Sends an HTTP/3 response on the specified stream with default priority.
 int quiche_h3_send_response(quiche_h3_conn *conn, quiche_conn *quic_conn,
                             uint64_t stream_id, quiche_h3_header *headers,
                             size_t headers_len, bool fin);
 
 // Sends an HTTP/3 response on the specified stream with specified priority.
 int quiche_h3_send_response_with_priority(quiche_h3_conn *conn,
                             quiche_conn *quic_conn, uint64_t stream_id,
                             quiche_h3_header *headers, size_t headers_len,
                             quiche_h3_priority *priority, bool fin);
 
 // Sends an HTTP/3 body chunk on the given stream.
 ssize_t quiche_h3_send_body(quiche_h3_conn *conn, quiche_conn *quic_conn,
                             uint64_t stream_id, uint8_t *body, size_t body_len,
                             bool fin);
 
 // Reads request or response body data into the provided buffer.
 ssize_t quiche_h3_recv_body(quiche_h3_conn *conn, quiche_conn *quic_conn,
                             uint64_t stream_id, uint8_t *out, size_t out_len);
 
 // Try to parse an Extensible Priority field value.
 int quiche_h3_parse_extensible_priority(uint8_t *priority,
                                         size_t priority_len,
                                         quiche_h3_priority *parsed);
 
 /// Sends a PRIORITY_UPDATE frame on the control stream with specified
 /// request stream ID and priority.
 int quiche_h3_send_priority_update_for_request(quiche_h3_conn *conn,
                                                quiche_conn *quic_conn,
                                                uint64_t stream_id,
                                                quiche_h3_priority *priority);
 
 // Take the last received PRIORITY_UPDATE frame for a stream.
 //
 // The `cb` callback will be called once. `cb` should check the validity of
 // priority field value contents. If `cb` returns any value other than `0`,
 // processing will be interrupted and the value is returned to the caller.
 int quiche_h3_take_last_priority_update(quiche_h3_conn *conn,
                                         uint64_t prioritized_element_id,
                                         int (*cb)(uint8_t  *priority_field_value,
                                                   uint64_t priority_field_value_len,
                                                   void *argp),
                                         void *argp);
 
 // Returns whether the peer enabled HTTP/3 DATAGRAM frame support.
 bool quiche_h3_dgram_enabled_by_peer(quiche_h3_conn *conn,
                                      quiche_conn *quic_conn);
 
 // Writes data to the DATAGRAM send queue.
 ssize_t quiche_h3_send_dgram(quiche_h3_conn *conn, quiche_conn *quic_conn,
                             uint64_t flow_id, uint8_t *data, size_t data_len);
 
 // Reads data from the DATAGRAM receive queue.
 ssize_t quiche_h3_recv_dgram(quiche_h3_conn *conn, quiche_conn *quic_conn,
                             uint64_t *flow_id, size_t *flow_id_len,
                             uint8_t *out, size_t out_len);
 
 // Frees the HTTP/3 connection object.
 void quiche_h3_conn_free(quiche_h3_conn *conn);
 
 #if defined(__cplusplus)
 }  // extern C
 #endif
 
 #endif // QUICHE_H